After reading my post about frogs and soles you should intuitively understand the first reason why horses should have low heels: The frog needs to touch the ground to work correctly. But the following pictures should show you another reason why the heels need to be low. Unnaturally high heels tip the coffin bone onto its tip. Even in the absence of diet-based laminitis, high heels can cause a kind of mechanical laminitis by levering the coffin bone away from the hoof wall.
More x rays for you, I bet you didn't know you'd get good at interpreting these:
|High heels and hoof wall separation, a vet would call this a rotation|
|High heels combined with a long toe|
|See how the tip of the coffin bone has eroded? Note how far P2 has descended inside the hoof capsule.|
|Slipper foot, note the looooong toe, high heel, and how the coffin bone has started to erode|
|This one is interesting, the heel isn't that high but the sole is thin and the toe is long. P2 has descended inside the hoof capsule.|
Want to know how long toes happen? If the horse starts landing toe first for some reason - be it thrush, poor trimming, diet, or something else - the laminae will start to tear. When the laminae starts to tear the body freaks out and sends in reinforcements to build more laminae, thus making the toe longer. This longer toe will cause even more tearing of the laminae, more reinforcements are sent, and the cycle goes on and on. What the horse ends up with is called a lamellar wedge: a nerveless, bloodless mass of excess material sort of similar to a callus or foot corn.
What do you do when you realize your horse has grown lamellar wedge? Cut it off. Seriously. I'm not talking about how farriers will rasp off the hoof wall at the toe (I don't think that's a good idea in general, thinning the hoof wall doesn't do anything good for the horse), I mean cut it off the hoof perpendicular to the ground- it certainly won't do your horse any favors if you leave it there.
Look back at those x rays and note that the coffin bone stays in the same alignment under the leg relative to the heels no matter how far out the toe has grown. Once you establish what the shape of the hoof should be based on the heel purchase, you can find exactly where your horse's toe should be.
|This photo from the Swedish Hoof School further emphasizes my point, toe moves out but the coffin bone doesn't.|
I took this photo of Coriander's right fore last November before I really understood this. See how long that toe was?
|Isn't it great that I have examples from my horses of all the bad things? Bleh. Note the thrushy frog.|
|This circle is actually a little big, but it still shows that he had a LOT of excess toe.|
But at that time I was still skeptical, and I didn't have nippers yet, so I only took half of it off and rockered the rest (A rocker is simply an angle rasped into the toe- a break-over aid.). Then we went for a ride. Holy cow! It was like he was a different horse. I couldn't believe how quickly he was picking up his front feet. It was amazing what a difference half an inch made.
Then something else interesting happened, he developed a toe callus.
One caveat: I probably wouldn't do that if the toe was really long (slipper foot) simply because it would remove too much hoof wall from the front of the foot. In that case I'd rocker the toe until the flare grew out a little more.
So there you go, there's almost a year's worth of hoof research distilled into a few posts. After all I've learned, I see horses all over the place with poor feet. All I can do is sit here and wonder, "How much better would those horses move if their feet were in better shape?" It's kind of depressing. Now maybe you'll see it too... you're welcome.